Looking through plus-sized creatures in the 5e Monster Manual, I am unable to find any monsters that can target more than one creature with a single melee attack. I would think that a huge-size giant, for example, could swing an axe in a large enough arc to hit several playable characters at once. Stat block descriptions for melee attacks always specify “one target”, indicating the possibility of multi-target attacks, but from what I can tell this is an unused feature. Attack descriptions for larger-sized creatures do generally have a longer reach, befitting the creature’s size, but that’s the extent of it.
Why It Matters to Me
I would like to homebrew a few creatures that can target more than one creature in a single melee attack, but I am suspicious about the fact that RAW materials do not seem to include such mechanics. I suspect multi-target melee attacks are absent for a good reason, and I would like to learn why this might be problematic before I unleash such a creature against my players.
Is there a specific game design reason why I should not create a creature with a multi-target melee attack? Specifically, I would like to edit creature stat blocks that would read like this:
Morningstar. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 21 (3d8 + 8) piercing damage.
to read like this:
Morningstar. Melee Weapon Attack: +12 to hit, reach 10 ft., two targets. Hit: 21 (3d8 + 8) piercing damage.
Is this a problem? Could making this change result in a game-breaking problem, or absurd outcome?